<?php

/*
 * This file is part of SwiftMailer.
 * (c) 2004-2009 Chris Corbyn
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

/**
 * The EventDispatcher which handles the event dispatching layer.
 *
 * @package    Swift
 * @subpackage Events
 * @author     Chris Corbyn
 */
class Swift_Events_SimpleEventDispatcher implements Swift_Events_EventDispatcher
{
	/** A map of event types to their associated listener types */
	private $_eventMap = array();

	/** Event listeners bound to this dispatcher */
	private $_listeners = array();

	/** Listeners queued to have an Event bubbled up the stack to them */
	private $_bubbleQueue = array();

	/**
	 * Create a new EventDispatcher.
	 */
	public function __construct()
	{
		$this->_eventMap = array(
			'Swift_Events_CommandEvent' => 'Swift_Events_CommandListener',
			'Swift_Events_ResponseEvent' => 'Swift_Events_ResponseListener',
			'Swift_Events_SendEvent' => 'Swift_Events_SendListener',
			'Swift_Events_TransportChangeEvent' => 'Swift_Events_TransportChangeListener',
			'Swift_Events_TransportExceptionEvent' => 'Swift_Events_TransportExceptionListener'
		);
	}

	/**
	 * Create a new SendEvent for $source and $message.
	 *
	 * @param Swift_Transport $source
	 * @param Swift_Mime_Message
	 *
	 * @return Swift_Events_SendEvent
	 */
	public function createSendEvent(Swift_Transport $source, Swift_Mime_Message $message)
	{
		return new Swift_Events_SendEvent($source, $message);
	}

	/**
	 * Create a new CommandEvent for $source and $command.
	 *
	 * @param Swift_Transport $source
	 * @param string $command That will be executed
	 * @param array $successCodes That are needed
	 *
	 * @return Swift_Events_CommandEvent
	 */
	public function createCommandEvent(Swift_Transport $source, $command, $successCodes = array())
	{
		return new Swift_Events_CommandEvent($source, $command, $successCodes);
	}

	/**
	 * Create a new ResponseEvent for $source and $response.
	 *
	 * @param Swift_Transport $source
	 * @param string $response
	 * @param boolean $valid If the response is valid
	 *
	 * @return Swift_Events_ResponseEvent
	 */
	public function createResponseEvent(Swift_Transport $source, $response, $valid)
	{
		return new Swift_Events_ResponseEvent($source, $response, $valid);
	}

	/**
	 * Create a new TransportChangeEvent for $source.
	 *
	 * @param Swift_Transport $source
	 *
	 * @return Swift_Events_TransportChangeEvent
	 */
	public function createTransportChangeEvent(Swift_Transport $source)
	{
		return new Swift_Events_TransportChangeEvent($source);
	}

	/**
	 * Create a new TransportExceptionEvent for $source.
	 *
	 * @param Swift_Transport $source
	 * @param Swift_TransportException $ex
	 *
	 * @return Swift_Events_TransportExceptionEvent
	 */
	public function createTransportExceptionEvent(Swift_Transport $source, Swift_TransportException $ex)
	{
		return new Swift_Events_TransportExceptionEvent($source, $ex);
	}

	/**
	 * Bind an event listener to this dispatcher.
	 *
	 * @param Swift_Events_EventListener $listener
	 */
	public function bindEventListener(Swift_Events_EventListener $listener)
	{
		foreach ($this->_listeners as $l) {
			// Already loaded
			if ($l === $listener) {
				return;
			}
		}
		$this->_listeners[] = $listener;
	}

	/**
	 * Dispatch the given Event to all suitable listeners.
	 *
	 * @param Swift_Events_EventObject $evt
	 * @param string $target method
	 */
	public function dispatchEvent(Swift_Events_EventObject $evt, $target)
	{
		$this->_prepareBubbleQueue($evt);
		$this->_bubble($evt, $target);
	}

	// -- Private methods

	/** Queue listeners on a stack ready for $evt to be bubbled up it */
	private function _prepareBubbleQueue(Swift_Events_EventObject $evt)
	{
		$this->_bubbleQueue = array();
		$evtClass = get_class($evt);
		foreach ($this->_listeners as $listener) {
			if (array_key_exists($evtClass, $this->_eventMap)
				&& ($listener instanceof $this->_eventMap[$evtClass])
			) {
				$this->_bubbleQueue[] = $listener;
			}
		}
	}

	/** Bubble $evt up the stack calling $target() on each listener */
	private function _bubble(Swift_Events_EventObject $evt, $target)
	{
		if (!$evt->bubbleCancelled() && $listener = array_shift($this->_bubbleQueue)) {
			$listener->$target($evt);
			$this->_bubble($evt, $target);
		}
	}
}
